Crane



March 7, 1939. L, @YOUNG 2,149,381

CRANE Filed Feb. l5, 1937 2Sheets-Sheet l vINVENTOR Lewis Gzung.

March 75 1939. G, kYQUNG, 2,149,381

CRANE Filed Feb. 15,v 1931 2 sheets-shew 2 INVENTOR l( /f/ Lewis G. Young. l l jfyT/W l/ M A ATTORNEY Patented Mar. 7, 1939 UNITED STATES PATENT OFFICE 7 Claims.

This invention relates to cranes and like mechanisms and more particularly to a crane of the mobile type, which is adapted to be attached to the tail piece of a tractor or like propelling mar. chine for transportationk where required.

It is proposed by this invention to provide in a mobile crane a pyramidally shaped boomwhereby increased stabilityand strength, lwill'be obvv tained, and the possibilityof tilting or buckling m substantially eliminated.

It is proposed to hinge the pyramidal boom at opposite corners of its triangular base to the cross piece of a T shaped supporting frame, the tail piece of the latter being adapted to be cons -nected tothe drawbarv of a suitable propelling means,v such as atractor. A broad tread wheel maybe journaled to each of the ends of the cross piece of the supportingV frame. It is also proposed to dispose the apex of the ltriangular baseof the boomover and supported upon the tail piece of the supporting frame whereby, when the boom is tilted, the'sides -of the base will form a lever arm against the endof which a lifting force is applied to raise the boom and its load ling tendencies, and decrease the power required forthis operation, aswell as'permitting'the-use of a shorter length of cable and the obtainment 7 of a more'rapid raising movement ofthe boom. 3o

parts being assembled andl disposed compactly thereon.

Afurther object of this invention is to provide simple in construction, inexpensive to manufacture, comparatively-easy to manipulate, strong, compact, and very eiiicient and durablev in use.

With the above and other objects in view the invention consists in the novel features and combinations of parts to be hereinafter described and claimed, with reference to the accompanying drawings wherein;

Figure 1 is a front elevational view of a crane embodying the features of this invention.

Figure 2 is a side elevational View of the same.

Figure 3 is a top plan view of the same.

Figure 4 is a vertical section of the crane boom and, by dotted lines, illustrates the position of the parts when the boom isl tilted.

Figure 5 is an enlarged view showing the cooperatingdisposition of certain of the parts when the boom is tilted.

Referring now to the drawings wherein like 55 @reference characters indicate like' parts throughand thereby relieve cable strains, prevent buck- By the above arrangementthe supporting frame for the boom may be of len'gtl-i-and:V the f 5 a crane of the above type which will be relatively f outl the several figures, the T shaped supporting frame I is horizontaly disposed with its cross piece I I at the front and its tail piece I2 extending rearwardly therefrom. A broad tread ground wheel I3 is journaled to each end of the cross piece I I and the rear end of the tail piece I2 has a bolt receiving bracket I4 secured thereto whereby it may be secured by a bolt to the drawbar |6 of a tractor or other suitable crane propelling means. The connection of the tail piece I2 of the frame I0 with the drawbar I6 of the tractor and the spaced apart wheels I3 form a three point suspension for the crane whereby it may be readily swung into and out of the position of use. Side braces Il and I8, extending angularly from an intermediate point on the tail piece I2 to a point adjacent each end of the cross piece II, are provided to laterally strengthen the frame Ill and to form a supporting surface for a part of the crane boom.

The crane boom is preferably fabricated of angle iron and is constituted by a triangular base having a cross bar I3 disposed across the front, and equal length side bars and 2| which extend rearwardly from the ends of the cross bar I9 and converge together to form the apex 22 of the triangularly formed base. Bars 23 and 24 extend from each end of the cross bar I9 upwardly, and converge together and with a bar 26, extending upwardly from the apex 22, at 25. Suitably spaced apart cross bracing bars 2l are provided to extend between the upwardly extending bars 23 and 24,l and cross bars 28 and 29 are provided to extend between the bar 26 and the bars 23 and 24 respectively.

The front cross bar I9 of the base of the boom is hinged to and upon the top of the cross piece I2 of the frame IIJ, by pivot pins or bolts 30, which pass through suitable brackets 3| and 32 respec- -tively secured to the cross piece I2 and the cross bar I9 and which are disposed, one pair adjacent each end of the cross bar I9. Bars 33 and 34 each bent to extend from points adjacent the apex 22, where they are connected to the side bars 20 and 2| respectively, angularly downwardly to the braces I1 and I8 respectively, along the top surface of the same as at 35 and are then curved upwardly to points adjacent the front end of the side bars 20 and 2| respectively,-to which they are connected. 'I'he bars 33 and 34, by seating upon the braces and I8 respectively, form spaced apart footings for the boom and maintain it tilted forwardly slightly out of the perpendicular with respect to the frame I0, and support a large proportion of the downward thrust of the weight of the boom, relieving the pivot pins 30 from this portion of the weight. The bars 33 and 34 with the pivot pins 30, form supporting means for the boom, when a load is being carried thereby and transported from one location to another by moving the entire crane, whereby sidewise tilting is prevented and stability is assured.

A bracket 36 is provided at the upper end 25 of the boom and is adapted to support a rotatable pulley 3l over which a cable 38 is led and directed downwardly into position to have its end fastened to the load, to be raised and carried by the crane.

Another pulley 39 is suitably journaled between the upwardly extending bars 23 and 24 adjacent the point they converge, and the cable 38 is led over this pulley and directed downwardly to and over a pulley 40, suitably journaled in a bracket 4l disposed on and secured to the tail piece I2 of the frame I!! adjacent the cross piece Il. From the pulley 40, the cable 28 is directed along the tail piece l 2 to a swivel pulley 42, from which it is led to a suitable winding drum 43 which may be mounted upon the crane propelling means if so desired. By manipulation of the drum 43 the cable 28 may be wound thereon to raise the load, or unwound therefrom to lower it in the usual manner.

The boom is raised from a tilted position, as shown in dotted lines in Figure 4, by manipulation of another winding drum 44 to wind up a cable 45 which is reeved through a set of pulley blocks 46 and 41. The block 46 is pivotally secured to the tail piece l2 by suitable means, such as an eyebolt 48 spaced forwardly from the rear end of the tail piece l2. The block 41 is secured to an elongated rod 49 by having an extension 50 of the block 41 pivotally connected to a bifurcated part l secured to one end of the rod 49. The other end of the rod 49 is pivotally secured at 52 to a bracket 53, secured to the boom at a point spaced upwardly from its base and disposed on the bar 26. A substantially V shaped bracket 54 is secured at the apex 22 to the base of the boom with it flaring sides 55 and 56 extending substantially laterally, and is adapted to receive the part 5l between these sides, when the boom is tilted forwardly sufficiently to dispose the bar 26 beyond an aligned position with a center line passed through the pivot 52 and the pivot point 55, between the block 46 and the bolt 48, for instance as shown in Figures 4 and 5.

When the boom is tilted suflciently to cause the part 5l to seat between the sides 55 and 156 within the V of the bracket 54, the side bars 29 and 2l of the base of the boom` constitute a lever arm of what is, in effect, a bell crank form, the other lever arm of which is constituted, by the upwardly extending bars 23 and 24. By winding up the cable 45 on the drum 44, a longitudinal pull is exerted upon the rod 49 and the force of this pull will be converted as is obvious from Figure 4 into a downwardly directed pressure upon the apex 22, due to the above described arrangement. This downwardly directed pressure upon the assumed lever arm of the bell crank form, constituted by the bars 23 and 2| and bars 23 and 24 swings the boom about its fulcrum or pivots 30 and raises the other arm of the bell crank form, constituted by the 'bars 23 and 24. In view of this arrangement, a relatively powerful and rapid swinging movement is given to the boom requiring but a minimum of power to be applied at the drum., and during the period when the greatest weight, constituted by the load andthe weight of the boom, is being raised. When the boom is raised sufficiently to assume a substantially vertical position the pull of the cable 45 and rod 49 upon the boom is along a straight line but no appreciable increase in power is required, due to the counterbalancing effect caused by the weight of the rearwardly extending boom base and footings 33 and 34. By the above arrangement only a comparatively short length of cable 45 is required, and the blocks 46 and lllmay be disposed relatively close to the boom, thus conserving lengthwise space for the crane and forming a compact mechanism.

It will be obvious that the drums 43 and 44 may be disposed other than upon the crane propelling means, for instance, upon the frame lll, and that suitable weights may be placed upon the tail piece I2 to counterbalance the crane, when the same is disconnected from a tractor or like propelling means, and in operation when crane is extended supporting or carrying heavy weights.

Because of the two points of support provided for the lcrane by the wheels I3, the crane may be turned vin horizontal rotation by a movement of the toe of the tail piece. The crane may be operated connected to a tractor and in this case, when the load is freed from its resting place and drawn t0 the end of the boom, the tractor may start and while in motion elevate the boom to its raised position, proceed to its destination, place itself and then lower its load by both extending the boom and lowering from the nose of the boom. It is, therefore, evident that the crane has distinct mobile advantages.

While there has been illustrated and described herein a preferred embodiment of this invention, it is to be understood that the same is not to be limited thereto in all of its details, as the same may be modified thereto in all of its details, as the same may be modified and changed without departing from the spirit and scope thereof as defined in the. appended claims.

Having thus fully described the invention what is claimed and for which it-is desired to obtain Letters Patent is:

l. In a crane, an upwardly extending boom comprising artri'angular base having a bar extending upwardly from each corner and converging together above said base, the base and the front of said boom being in the form of isosceles trianglesfand the sides being in the form of right angle triangles, a horizontal support for said boom and to which one side of said base is hinged, and a support engaging member depending'from said base to engage said support between the hinged side of said base and its apex and to space the base from said support to maintain the front of said boom in a tilted position.

2. In a crane, an upwardly extending boom, a support for said boom, said boom including a base, the forward end of which is hinged to said support, whereby said boom isadapted to be swung between raised and lowered positions, and a boom swinging device connected to said boom, above the rearward end of the base opposite the hinged side, and connected to said support at a point rearwardly o-f and below said base, a straight line between said points of connection being rearwardly of said rearward end of the base in the raised position of said boom and intersecting said base between its forward and rearward ends in the lowered position, and means on saidv boom below the point of connection of said swingingdevic'e adapted to be engaged by said boom swinging device in said lowered position, whereby the pull of said swinging device is applied to the boom at a lower point in said loweredposition.

3. In a crane, an upwardly extending boom, a support for said boom, said boom including a triangular base, one side of which is hinged to said support, and side portions extending upwardly and converging together, a rod connected at one end to said boom above the corner of said base opposite its hinged side, a cable connected tothe other end of said rod, means to impose a pull on said cable, and a rod end receiving member onthe corner of the base opposite its hinged side. l

4. In a crane, a boom including a substantially upright first member, having a second memberv secured to and extending rearwardly from the bottom end thereof, and being hinged at its bottom end to a support, a third member extending upwardly from the rear end of said second member and converging toward the upper end of said rst member, a. rod connected to said third member at a point spaced upwardly from the rear end of said second member, a rod end receiving part on the rear end of said second member, a cable connected to the end of said rod received in said part, and a device to wind up said cable.

5. In a crane, a boom including a horizontally extending front base member, a support to which said front base member is hinged, a rearwardly extending base member, and a member extending upwardly from said front base member, a rod connected at one end to said boom above said rearwardly extending base member, a rod receivingmember at the end of said rearwardly extending base member to receive the other end of said rod, and means to cause said rod to impose a downwardly directed pressure on the end of said rearwardly extending base member to rock said boom about the hinged connection between the support and the front base member.

6. In a crane, a support, an upwardly extending boom hinged at its lower end to said support, said boom having a rearwardly extending member, and means to impose a downward pull upon the rear end of said member when said boom is tilted to swing said boom relatively to said support, said means including a rod pivoted at one end to said boom above the rear end of said member, the other end of said rod being adapted to engage the rear end of said member when said boom is tilted forwardly and a cable connected between said tie rod and said support, a straight line between the points of connection of said rod with said boom and said cable with said support being rearwardly of the rear end of said member in the non-tilted position of said boom and intersecting said member between the hinged point and said rear end in the forwardly tilted position of said boom.

7. In a crane, an upwardly extending boom constituted by a triangular base having a bar extending upwardly from each corner and converging together above said base, a support for said boom and to which one side of said base is hinged, a support engaging member depending from said base to space the apex thereof from said support to maintain the boom in a normally slightly forwardly tilted position, a rod pivotally connected at one end to said boom above the apex of said base, the other end of said rod being adapted to engage the apex of said base, when said boom is tilted forwardly, to raise a load and means to impose a downward pull on said last mentioned end of said rod to cause rocking of said boom relatively to said support into its normal position.

LEWIS G. YOUNG. 

